Feature request

to_a2a() currently requires host, port, and protocol as separate parameters:

app = to_a2a(
    root_agent,
    host="localhost",
    port=8002,
    protocol="http",
    runner=_create_runner,
    agent_card=agent_card,
)

In practice, the service URL is typically available as a single string (e.g. SERVICE_URL=http://localhost:8002 for local dev, or https://my-agent.europe-west1.run.app on Cloud Run). This forces every consumer to manually parse the URL with urlparse() to extract the three components:

parsed = urlparse(settings.SERVICE_URL)
protocol = parsed.scheme or "http"
host = parsed.hostname or "localhost"
port = parsed.port or (443 if protocol == "https" else 80)

Proposal

Accept an optional service_url parameter as an alternative to host/port/protocol:

# New — single URL string
app = to_a2a(root_agent, service_url="http://localhost:8002", ...)

# Existing — still works
app = to_a2a(root_agent, host="localhost", port=8002, protocol="http", ...)

This would reduce boilerplate for Cloud Run, Kubernetes, and any deployment where the URL comes from an environment variable.